Classified the loose functions in metadata.py

metadata.py

@@ -14,20 +14,8 @@ import sqlalchemy.orm
 # TODO: l o g g i n g
 HASH_CHUNK_SIZE = 10485760 # 10mb
 
-db_session = None
-
-_db_session_maker = sqlalchemy.orm.sessionmaker()
-_engine = None
-_configured = False
 _SQLBase = sqlalchemy.ext.declarative.declarative_base()
 
-class MetadataDBSessionException(Exception):
-	'''This exception is raised when something goes wrong with a database session.'''
-
-
-def _uuidgen():
-	return str(uuid.uuid4())
-
 '''
 Metadata ORM classes for SQLAlchemy. For a detailed description of each piece of data, refer to
 metadata/README.md
@@ -112,63 +100,69 @@ class Image(_SQLBase):
 				)
 			)
 
-
+class hashdb:
-'''
+	_engine = None
-# TODO: I was attempting to avoid writing a class to see if I could, but it is not worth the clunk.
+
-Rewrite these functions into a class.
+	# TODO: db_path's default should be set here, not in frontend.
-'''
+	def __init__(self, db_path):
-
+		'''
-def configure(db_path):
+		Configure and initialize the database for the entire module.
-	'''
+		Currently, only SQLite is supported.
-	Configure and initialize the database for the entire module.
+
-	Currently, only SQLite is supported.
+		db_path: Path for the SQLite database
-
+		'''
-	db_path: Path for the SQLite database
+		self._engine = sqlalchemy.create_engine('sqlite:///%s' % db_path)
-	'''
+
-	_engine = sqlalchemy.create_engine('sqlite:///%s' % db_path)
+		_SQLBase.metadata.create_all(self._engine)
-
+		self._session_maker.configure(bind=self._engine)
-	_SQLBase.metadata.create_all(_engine)
+
-	_db_session_maker.configure(bind=_engine)
+	def search(self, table_object, **constraints):
-	_configured = True
+		'''
-
+		Search the database for entries matching the given constraints.
-def search(session, table_object, **constraints):
+
-	'''
+		table_object: SQLAlchemy ORM table object, defined in the file above
-	Search the database for entries matching the given constraints.
+		constraints: key-value pairs to match against specific fields in the database
-
+					Note: Currently, only the query.ilike method is supported. This is intended to
-	session: SQLAlchemy session, presumably from get_db_session
+					eventually support the entire range of available filters.
-	table_object: SQLAlchemy ORM table object, defined in the file above
+		'''
-	constraints: key-value pairs to match against specific fields in the database
+
-				Note: Currently, only the query.ilike method is supported. This is intended to
+		with self._get_db_session() as session:
-				eventually support the entire range of available filters.
+			# TODO: Consider making this return data recursively on items that reference other
-	'''
+			#	tables.
-	query = session.query(table_object)
+			query = session.query(table_object)
-
+
-	for key, value in constraints.items():
+			for key, value in constraints.items():
-		query = query.filter(getattr(table_object, key).ilike('%%%s%%' % value))
+				query = query.filter(getattr(table_object, key).ilike('%%%s%%' % value))
-
+
-	item_list = []
+			item_list = []
-	for item in query:
+			for item in query:
-		item_list.append(item)
+				item_list.append(item)
-
+
-	return item_list
+		return item_list
-
+
-@contextlib.contextmanager
+	def import_json(self, json_file):
-def get_db_session():
+		'''
-	'''Get a SQLAlchemy database session with a proper context object. '''
+		Import metadata from a json file.
-	# TODO: There's probably a more reliable way of knowing whether the database was configured.
+		'''
-	if not _configured:
+
-		raise MetadataDBSessionException('Tried to get session without configuring a database.')
+		# json files can be large, but not too large for ram
-
+		# do not exit on invalid metadata, log the error and skip the object
-	session = _db_session_maker()
+		pass
-	try:
+
-		yield session
+	@contextlib.contextmanager
-
+	def _get_db_session():
-	except:
+		'''Get a SQLAlchemy database session with a proper context object. '''
-		# TODO: Decide which exceptions to handle/eat here and which ones belong in UI.
+
-		#   This one is okay to put off until you start really building UI.
+		session = sqlalchemy.orm.sessionmaker()
-		session.rollback()
+		try:
-		raise
+			yield session
-	else:
+
-		session.commit()
+		except:
-	finally:
+			# TODO: Decide which exceptions to handle/eat here and which ones belong in UI.
-		session.close()
+			#   This one is okay to put off until you start really building UI.
+			session.rollback()
+			raise
+		else:
+			session.commit()
+		finally:
+			session.close()